I did not see much evidence of story line anywhere in the leak. It looked entirely like resource collection and vanilla game mechanics.
No checkpoints were visible even. I think it's far more likely that this game will be about "open world" and "multiplayer" combat and driving mechanics, centered around resource collection.
That's not been my experience. Typically both are developed in parallel. The integration of the story into the dev build might come later, but certain entities that enable story development should be there. Things like checkpoints, non-background characters, locations/state driven events, unique items and environments, etc... What I saw in this leak did not include anything that - it all seem generic, and that pile-o-cash loot item highlights what the mission reward system is going to be like.
No checkpoints were visible even. I think it's far more likely that this game will be about "open world" and "multiplayer" combat and driving mechanics, centered around resource collection.